IL17A and Behcet disease: In patients with BD and early gastrointestinal involvement, both Th1 and Th17 cells infiltrating the intestinal mucosa were suggested to be key drivers of inflammation, causing mucosal damage via increased production of pro-inflammatory cytokines (e.g., IL-17, interferon [IFN]-γ), along with intestinal T-cells that produce large quantities of TNF-α [30].